| /* |
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| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
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| * accompanied this code). |
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| |
| /* |
| * This file is available under and governed by the GNU General Public |
| * License version 2 only, as published by the Free Software Foundation. |
| * However, the following notice accompanied the original version of this |
| * file: |
| * |
| * Copyright (c) 2012, Stephen Colebourne & Michael Nascimento Santos |
| * |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are met: |
| * |
| * * Redistributions of source code must retain the above copyright notice, |
| * this list of conditions and the following disclaimer. |
| * |
| * * Redistributions in binary form must reproduce the above copyright notice, |
| * this list of conditions and the following disclaimer in the documentation |
| * and/or other materials provided with the distribution. |
| * |
| * * Neither the name of JSR-310 nor the names of its contributors |
| * may be used to endorse or promote products derived from this software |
| * without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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| * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| package java.time.temporal; |
| |
| import java.time.DateTimeException; |
| import java.util.Objects; |
| |
| /** |
| * Framework-level interface defining read-only access to a temporal object, |
| * such as a date, time, offset or some combination of these. |
| * <p> |
| * This is the base interface type for date, time and offset objects. |
| * It is implemented by those classes that can provide information |
| * as {@linkplain TemporalField fields} or {@linkplain TemporalQuery queries}. |
| * <p> |
| * Most date and time information can be represented as a number. |
| * These are modeled using {@code TemporalField} with the number held using |
| * a {@code long} to handle large values. Year, month and day-of-month are |
| * simple examples of fields, but they also include instant and offsets. |
| * See {@link ChronoField} for the standard set of fields. |
| * <p> |
| * Two pieces of date/time information cannot be represented by numbers, |
| * the {@linkplain java.time.chrono.Chronology chronology} and the |
| * {@linkplain java.time.ZoneId time-zone}. |
| * These can be accessed via {@linkplain #query(TemporalQuery) queries} using |
| * the static methods defined on {@link TemporalQuery}. |
| * <p> |
| * A sub-interface, {@link Temporal}, extends this definition to one that also |
| * supports adjustment and manipulation on more complete temporal objects. |
| * <p> |
| * This interface is a framework-level interface that should not be widely |
| * used in application code. Instead, applications should create and pass |
| * around instances of concrete types, such as {@code LocalDate}. |
| * There are many reasons for this, part of which is that implementations |
| * of this interface may be in calendar systems other than ISO. |
| * See {@link java.time.chrono.ChronoLocalDate} for a fuller discussion of the issues. |
| * |
| * @implSpec |
| * This interface places no restrictions on the mutability of implementations, |
| * however immutability is strongly recommended. |
| * |
| * @since 1.8 |
| */ |
| public interface TemporalAccessor { |
| |
| /** |
| * Checks if the specified field is supported. |
| * <p> |
| * This checks if the date-time can be queried for the specified field. |
| * If false, then calling the {@link #range(TemporalField) range} and {@link #get(TemporalField) get} |
| * methods will throw an exception. |
| * |
| * @implSpec |
| * Implementations must check and handle all fields defined in {@link ChronoField}. |
| * If the field is supported, then true must be returned, otherwise false must be returned. |
| * <p> |
| * If the field is not a {@code ChronoField}, then the result of this method |
| * is obtained by invoking {@code TemporalField.isSupportedBy(TemporalAccessor)} |
| * passing {@code this} as the argument. |
| * <p> |
| * Implementations must ensure that no observable state is altered when this |
| * read-only method is invoked. |
| * |
| * @param field the field to check, null returns false |
| * @return true if this date-time can be queried for the field, false if not |
| */ |
| boolean isSupported(TemporalField field); |
| |
| /** |
| * Gets the range of valid values for the specified field. |
| * <p> |
| * All fields can be expressed as a {@code long} integer. |
| * This method returns an object that describes the valid range for that value. |
| * The value of this temporal object is used to enhance the accuracy of the returned range. |
| * If the date-time cannot return the range, because the field is unsupported or for |
| * some other reason, an exception will be thrown. |
| * <p> |
| * Note that the result only describes the minimum and maximum valid values |
| * and it is important not to read too much into them. For example, there |
| * could be values within the range that are invalid for the field. |
| * |
| * @implSpec |
| * Implementations must check and handle all fields defined in {@link ChronoField}. |
| * If the field is supported, then the range of the field must be returned. |
| * If unsupported, then an {@code UnsupportedTemporalTypeException} must be thrown. |
| * <p> |
| * If the field is not a {@code ChronoField}, then the result of this method |
| * is obtained by invoking {@code TemporalField.rangeRefinedBy(TemporalAccessorl)} |
| * passing {@code this} as the argument. |
| * <p> |
| * Implementations must ensure that no observable state is altered when this |
| * read-only method is invoked. |
| * <p> |
| * The default implementation must behave equivalent to this code: |
| * <pre> |
| * if (field instanceof ChronoField) { |
| * if (isSupported(field)) { |
| * return field.range(); |
| * } |
| * throw new UnsupportedTemporalTypeException("Unsupported field: " + field); |
| * } |
| * return field.rangeRefinedBy(this); |
| * </pre> |
| * |
| * @param field the field to query the range for, not null |
| * @return the range of valid values for the field, not null |
| * @throws DateTimeException if the range for the field cannot be obtained |
| * @throws UnsupportedTemporalTypeException if the field is not supported |
| */ |
| default ValueRange range(TemporalField field) { |
| if (field instanceof ChronoField) { |
| if (isSupported(field)) { |
| return field.range(); |
| } |
| throw new UnsupportedTemporalTypeException("Unsupported field: " + field); |
| } |
| Objects.requireNonNull(field, "field"); |
| return field.rangeRefinedBy(this); |
| } |
| |
| /** |
| * Gets the value of the specified field as an {@code int}. |
| * <p> |
| * This queries the date-time for the value of the specified field. |
| * The returned value will always be within the valid range of values for the field. |
| * If the date-time cannot return the value, because the field is unsupported or for |
| * some other reason, an exception will be thrown. |
| * |
| * @implSpec |
| * Implementations must check and handle all fields defined in {@link ChronoField}. |
| * If the field is supported and has an {@code int} range, then the value of |
| * the field must be returned. |
| * If unsupported, then an {@code UnsupportedTemporalTypeException} must be thrown. |
| * <p> |
| * If the field is not a {@code ChronoField}, then the result of this method |
| * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} |
| * passing {@code this} as the argument. |
| * <p> |
| * Implementations must ensure that no observable state is altered when this |
| * read-only method is invoked. |
| * <p> |
| * The default implementation must behave equivalent to this code: |
| * <pre> |
| * if (range(field).isIntValue()) { |
| * return range(field).checkValidIntValue(getLong(field), field); |
| * } |
| * throw new UnsupportedTemporalTypeException("Invalid field " + field + " + for get() method, use getLong() instead"); |
| * </pre> |
| * |
| * @param field the field to get, not null |
| * @return the value for the field, within the valid range of values |
| * @throws DateTimeException if a value for the field cannot be obtained or |
| * the value is outside the range of valid values for the field |
| * @throws UnsupportedTemporalTypeException if the field is not supported or |
| * the range of values exceeds an {@code int} |
| * @throws ArithmeticException if numeric overflow occurs |
| */ |
| default int get(TemporalField field) { |
| ValueRange range = range(field); |
| if (range.isIntValue() == false) { |
| throw new UnsupportedTemporalTypeException("Invalid field " + field + " for get() method, use getLong() instead"); |
| } |
| long value = getLong(field); |
| if (range.isValidValue(value) == false) { |
| throw new DateTimeException("Invalid value for " + field + " (valid values " + range + "): " + value); |
| } |
| return (int) value; |
| } |
| |
| /** |
| * Gets the value of the specified field as a {@code long}. |
| * <p> |
| * This queries the date-time for the value of the specified field. |
| * The returned value may be outside the valid range of values for the field. |
| * If the date-time cannot return the value, because the field is unsupported or for |
| * some other reason, an exception will be thrown. |
| * |
| * @implSpec |
| * Implementations must check and handle all fields defined in {@link ChronoField}. |
| * If the field is supported, then the value of the field must be returned. |
| * If unsupported, then an {@code UnsupportedTemporalTypeException} must be thrown. |
| * <p> |
| * If the field is not a {@code ChronoField}, then the result of this method |
| * is obtained by invoking {@code TemporalField.getFrom(TemporalAccessor)} |
| * passing {@code this} as the argument. |
| * <p> |
| * Implementations must ensure that no observable state is altered when this |
| * read-only method is invoked. |
| * |
| * @param field the field to get, not null |
| * @return the value for the field |
| * @throws DateTimeException if a value for the field cannot be obtained |
| * @throws UnsupportedTemporalTypeException if the field is not supported |
| * @throws ArithmeticException if numeric overflow occurs |
| */ |
| long getLong(TemporalField field); |
| |
| /** |
| * Queries this date-time. |
| * <p> |
| * This queries this date-time using the specified query strategy object. |
| * <p> |
| * Queries are a key tool for extracting information from date-times. |
| * They exists to externalize the process of querying, permitting different |
| * approaches, as per the strategy design pattern. |
| * Examples might be a query that checks if the date is the day before February 29th |
| * in a leap year, or calculates the number of days to your next birthday. |
| * <p> |
| * The most common query implementations are method references, such as |
| * {@code LocalDate::from} and {@code ZoneId::from}. |
| * Additional implementations are provided as static methods on {@link TemporalQuery}. |
| * |
| * @implSpec |
| * The default implementation must behave equivalent to this code: |
| * <pre> |
| * if (query == TemporalQueries.zoneId() || |
| * query == TemporalQueries.chronology() || query == TemporalQueries.precision()) { |
| * return null; |
| * } |
| * return query.queryFrom(this); |
| * </pre> |
| * Future versions are permitted to add further queries to the if statement. |
| * <p> |
| * All classes implementing this interface and overriding this method must call |
| * {@code TemporalAccessor.super.query(query)}. JDK classes may avoid calling |
| * super if they provide behavior equivalent to the default behaviour, however |
| * non-JDK classes may not utilize this optimization and must call {@code super}. |
| * <p> |
| * If the implementation can supply a value for one of the queries listed in the |
| * if statement of the default implementation, then it must do so. |
| * For example, an application-defined {@code HourMin} class storing the hour |
| * and minute must override this method as follows: |
| * <pre> |
| * if (query == TemporalQueries.precision()) { |
| * return MINUTES; |
| * } |
| * return TemporalAccessor.super.query(query); |
| * </pre> |
| * <p> |
| * Implementations must ensure that no observable state is altered when this |
| * read-only method is invoked. |
| * |
| * @param <R> the type of the result |
| * @param query the query to invoke, not null |
| * @return the query result, null may be returned (defined by the query) |
| * @throws DateTimeException if unable to query |
| * @throws ArithmeticException if numeric overflow occurs |
| */ |
| default <R> R query(TemporalQuery<R> query) { |
| if (query == TemporalQueries.zoneId() |
| || query == TemporalQueries.chronology() |
| || query == TemporalQueries.precision()) { |
| return null; |
| } |
| return query.queryFrom(this); |
| } |
| |
| } |
